Is it possible to edit contents of e-mail messages (including headers) in any mailbox stored on Exchange Server (Exchange Server 2010 SP3 UR2 - 14.3.158.1)? Or, alternatively, edit the email messages in the OST file (of MS Outlook), so that they then can be synchronized with the Exchange server? PS. This is necessary for the same functionality as in this email editor in Gmail: Signal Extension for Chrome